The present invention is directed to bicycle components and, more particularly, to a bicycle shock absorber wherein the elastic shock absorber elements are efficiently placed within the shock absorber.
Cycling grows in popularity not only as a transportation means but, to a greater extent, as a mode of recreation. In addition, cycling is a popular competitive sport for professionals and amateurs. It is known that mountain and road bicycles are currently provided with front or rear suspensions to absorb shocks transmitted to the rider both on and off the road. Numerous structures, ranging from simple to complex, are used for such suspensions. For example, Japanese Unexamined Patent Application 9-290790 teaches an inexpensive bicycle suspension with a simple structure. This suspension comprises a cylindrical external member with a plurality of projections extending inwardly and an internal member mounted inside the external member and having a plurality of projections extending radially outwardly, wherein the plurality of projections extending from the external member radially face the plurality of projections extending from the internal member. Elastic members are mounted between the external member and the internal member and are compressionally deformed by the relative rotation of the two members. Side plates are integrally attached to both ends of the internal member. The external and internal members may be integrally linked to respective front and rear frame members of the bicycle, wherein the rear frame member is fixed to the side plates. The elastic members, which are interposed between the internal member and the external member, generate reaction force when compressed by the relative rotation of the two members.
In the conventional bicycle suspension described above, the elastic members are merely interposed in the space between the internal member and the external member, and hence sometimes slip and change their configuration in the space between the two members when compressed only slightly. A change in the configuration of the elastic members alters the state of the system during compression and results in a varying, unstable shock absorption performance. In view of this, it was suggested to place the elastic members in compact fashion in the space between the two members in order to prevent changes in configuration. However, compact placement of the elastic members makes it more difficult for the elastic members being compressed to expand, markedly increases the reaction force of the two members per unit angle of rotation, and it fails to ensure adequate shock absorption.
The present invention is directed to a bicycle shock absorber which provides stable shock absorption characteristics. In one embodiment of the present invention, a shock absorber for mounting between a first frame member and a second frame member of a bicycle includes a first member adapted to couple to the first frame member and a second member adapted to couple to the second frame member, wherein the first member and the second member rotate relative to each other. The first member includes a first member protrusion extending inwardly from an inner surface thereof and forming a first border surface at a junction of the first member protrusion and the inner surface. Similarly, the second member includes a second protrusion extending outwardly from an outer surface thereof and forming a second border surface at a junction of the second member protrusion and the outer surface. The first member protrusion faces the second member protrusion in a circumferential direction. An elastic member is disposed between the first member protrusion and the second member protrusion and contacts at least one of the first border surface and the second border surface. If desired, a first space may be defined on a first side surface of the first member protrusion facing the second member protrusion in the circumferential direction, and a second space may be defined on a second side surface of the first member protrusion, wherein the first elastic member is disposed in the first space. A second elastic member may be disposed in the second space.
In another embodiment of the present invention, a shock absorber for mounting between a first frame member and a second frame member of a bicycle includes a first member adapted to couple to the first frame member and a second member adapted to couple to the second frame member, wherein the first member and the second member rotate relative to each other. The first member includes a first member protrusion extending inwardly from an inner surface thereof, and the second member includes a second protrusion extending outwardly from an outer surface thereof. The first member protrusion faces the second member protrusion in a circumferential direction. An elastic member is disposed between the first member protrusion and the second member protrusion, wherein a side surface of the first elastic member contacts a facing side surface of at least one of the first member protrusion and the second member protrusion along substantially an entire length of the at least one of the first member protrusion and the second member protrusion. Additionally, the side surface of the first elastic member has a same shape as the facing side surface of the at least one of the first member protrusion and the second member protrusion when the first elastic member is in an uncompressed state.
In yet another embodiment of the present invention, a shock absorber for mounting between a first frame member and a second frame member of a bicycle includes a first member adapted to couple to the first frame member, wherein the first member includes at least one first member protrusion extending inwardly from an inner surface thereof; and a second member adapted to couple to the second frame member, wherein the second member includes at least one second member protrusion extending outwardly from an outer surface thereof. The first member and the second member rotate relative to each other. At least one of the first member protrusion and the second member protrusion has a first space defined on a first side surface thereof and a second space defined on an opposite second side surface thereof. The first space has a first circumferential area, and the second space has a second circumferential area. The first circumferential area is greater than the second circumferential area, and an elastic member is disposed in the first space.
In yet another embodiment of the present invention, a shock absorber for mounting between a first frame member and a second frame member of a bicycle includes a first member adapted to couple to the first frame member, wherein the first member includes at least one first member protrusion extending inwardly from an inner surface thereof; and a second member adapted to couple to the second frame member, wherein the second member includes at least one second member protrusion extending outwardly from an outer surface thereof. The first member and the second member rotate relative to each other. At least one of the first member protrusion and the second member protrusion has a first space defined on a first side surface thereof and a second space defined on an opposite second side surface thereof. The first space has a first circumferential width, and the second space has a second circumferential width measured at a same radial distance as the first circumferential width. The first circumferential width is greater than the second circumferential width, and a first elastic member is disposed in the first space.